This invention relates to a heat exchanger construction of a type which includes a separable core with the core construction being formed from a plurality of cut and formed metal sheets.
Heat exchangers using metal cores are particularly effective in high efficiency of heat transfer and also resistant to high heat values or high pressure values in comparison with cores using plastic materials. One disadvantage of the use of metal sheets for forming the core has however been the relatively high cost of manufacture involved in folding and forming the sheets into a cell structure, providing suitable spacers for the cells and then assembling the spaced cells into a unitary core construction.
In many cases welding of the sheets to form the cell structure has been used which provides a very rigid structure which is very resistant to heat and pressure but this is of course a highly expensive process involving much labor.
Other techniques are shown in U.S. Pat. Nos. 4,442,886 (Dinulescu), 4,512,397 (Stark), T911,013 (Morgans), 4,527,622 (Weber), 4,308,915 (Sanders), 2,434,676 (Spender) and 4,350,201 (Steineman).
Attention is particularly directed to the Sanders patent which shows an arrangement in which a single sheet is folded to form a planar plate portion and then side edges of the plate portion are folded at right angles and then inwardly and outwardly to define two tab portions generally parallel to the planar plate portion. The planar plate portions are then assembled in stacked arrangement but then a sealing or welding technique is used to separate the fluid paths.
In addition attention is directed to the Dinulescu patent which again shows separate sheets or plates folded into a particular shape but then these plates cooperate with spacer bars which run along the edges of the plates to hold them at the required spacing. This technique is unsatisfactory in that it involves a large number of separate parts which are difficult to assemble and of course require individual bending and forming.